The present disclosure relates to improved nickel beryllium alloy compositions. More particularly, the nickel beryllium alloy compositions of the instant application display improved corrosion resistance and galling resistance compared to existing nickel beryllium alloys.
Alloy 360™ is a known nickel-beryllium alloy provided by Materion Corporation (Cleveland, Ohio) that combines unique mechanical and physical properties required in high reliability elertrical/electronic systems, heavy duty controls, electromechanical devices and in other high performance applications. The chemical composition of Alloy 360™ includes about 1.85 wt % to 2.05 wt % beryllium and about 0.4 wt % to 0.6 wt % titanium, with the balance being nickel. A strip of nickel-beryllium Alloy 360™ has an ultimate tensile strength approaching about 300,000 psi, yield strength up to about 245,000 psi, flexible formability properties, stress relaxation less than about 5% at 400° F., and fatigue strength (in reverse bending) of about 85,000-90,000 psi at about 10 million cycles. Nickel-beryllium Alloy 360™ is used for mechanical and electrical/electronic components that are subjected to elevated temperatures (up to 700° F./350° C. for short times) and require good spring characteristics at these temperatures. Some applications for this alloy include thermostats, bellows, diaphragms, burn-in and test sockets. Nickel-beryllium Alloy 360™ is also used for high-reliability, corrosion resistant belleville washers in fire protection sprinkler heads among other things.
However, Alloy 360™ can be difficult to process due to discontinuous transformations in the alloy and a coarse microstructure in the as-cast and as-hot rolled form. In addition, the strength and hardness of the alloy is limited by its composition. It would be desirable to develop new alloy compositions with improved hardenability and processing capability relative to existing nickel-beryllium alloys.